Flywheel Installation; Testing The Ignition System - Generac Power Systems GN190H Service And Repair Manual

Use a commercially available flywheel puller to remove the
flywheel from the engine tapered shaft.

FLYWHEEL INSTALLATION:

Align the keyway in the flywheel with the woodruff key on
the crankshaft. Install the flywheel, the conical washer and
the starter cup. Install the flywheel nut and tighten to the
proper torque.
NOTE: The conical washer must be installed in the
proper direction (see Figure 8.4) with the convex side
facing out (away from the flywheel).
TORQUE SPECIFICATION
FLYWHEEL NUT
75 foot-pounds
WOODRUFF
KEY
CONVEX SIDE OF CONICAL
WASHER FACING OUT
FLYWHEEL
NUT
STARTER
CUP
FLYWHEEL
Figure 8.4 — Exploded View of Flywheel Assembly

TESTING THE IGNITION SYSTEM

Use a spark tester to test the ignition system. Such spark
testers are commercially available. Test the system as fol-
lows:
1. Disconnect the high tension lead from the spark plug.
2. See Figure 8.5. Attach the spark tester clamp to the engine
cylinder head (frame ground). Attach the spark plug high
tension lead to the tester terminal.
3. Crank the engine rapidly. If spark jumps the gap of the spark
tester, you may assume the ignition system is operating sat-
isfactorily.
FLYWHEEL
STARTER
CUP
CONICAL
WASHER
FLYWHEEL
NUT
Figure 8.5 — Testing Ignition System
NOTE: If the flywheel key is sheared or partially sheared,
spark can jump the tester gap. However, loss of correct
ignition timing may result in hard starting or no start-
ing at all.
4. To determine if an engine miss is ignition related, connect
the spark tester in series with the high tension lead and the
spark plug (Figure 8.6). Then, test the system as follows:
a. Start the engine.
b. If spark jumps the tester gap regularly but the miss con-
tinues, the problem is in the spark plug or in the fuel
system. A spark miss will be readily apparent.
Figure 8.6 — Checking for Engine Miss
NOTE: The ignition system described in this section is
typically used on horizontal shaft engines. The ignition
system used on all vertical shaft (RV) engines differs
from that of horizontal shaft engines. See "SERVICE
MANUAL COMPUTER CONTROLLED VARIABLE SPEED RV
GENERATORS," Manual Part No. 94468-A.
31
SECTION 8: IGNITION SYSTEM